Well, you need to understand that what you want/like is not always possible. This spec is written by Microsoft and we have to follow the spec for compatibility.
They surely believed “no one will ever do this”, but we know, technicians like to be proved wrong by users… ;)

Please also understand that several people of these 820 recipients could not see your email because their email clients could/will also not handle this.
Insisting in doing it might be “OK for you”, but be aware that people could actually not get your message.